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Boeing Clean Sheet Y1.5 "Light Twin" Study  
User currently offlineKeesje From , joined Dec 1969, posts, RR:
Posted (4 years 9 months 5 days 19 hours ago) and read 18982 times:

.
Hi, earlier this yr Rheinbote did a thread here on Civil Aviation on the Boeing 737/757 RS study http://www.airliners.net/aviation-fo...eneral_aviation/read.main/4286853/

However the complete article / details were not available by that time. Now they are  yummy  :
http://www.zinio.com/reader.jsp?issue=356227572&o=int&prev=sub&p=44

Some bullets :
 arrow  Boeing sees a market requirement Intra/Trans Asia, North America and Europe
 arrow  Twin aisles
 arrow  Short / medium haul, 2500-3200 nmi, Boeing resists calls for more range
 arrow  Around 757-300 capacity, 250-300 seats.
 arrow  Concepts were discussed with European Airlines
 arrow  Boeing acknowledges the 787-3 is compromised being a derivative of the long range 787-8
 arrow  Potential return to "more hydraulics"..

Good engines would IMO be crucial. I wonder if the LeapX / GTF could handle the required 40-43 klbs. Last week I started a more technical discussion on new engines / open rotor progress on Tech/Ops. http://www.airliners.net/aviation-forums/tech_ops/read.main/258685/

I have the feeling Airbus and Boeing purposely keeping a low profile but are all but sitting on their hands on the 737/757/A320 successors.

The enormous 737 / A320 backlogs IMO ain't what they look like, both Airbus and Boeing are cutting back production. Who wants to get their 737 in 2014 for use until 2039? Is it a smart investment?

The article seems to confirm the A321 and 737-900ER are not the 90% replacement for 757-200/ 757-300 /767-200/ TU154/ A300/ A310 some claim it to be. Of course airlines use 739/A321s, 757 wear out and there simply exist no alternatives at this moment.



Last month Airbus also indicated it is looking at broader solutions then just A320 series replacement. Quote of interest on the GTF : "Airbus is considering this new technology as a fallback technology should open-rotor not work out.  scratchchin 
http://www.ainonline.com/news/single...ptions-for-next-narrowbody-models/

50 replies: All unread, showing first 25:
 
User currently offlineThegeek From Australia, joined Nov 2007, 2638 posts, RR: 0
Reply 1, posted (4 years 9 months 5 days 8 hours ago) and read 18764 times:

That's interesting. I have been wondering if there would be a market for a shorter range wide body, given that once the A330 goes out of production, there won't be any wide bodies on the market optimised for range less than 744 range, assuming the 787 & A350 meet their range targets.

It hasn't been tried since the A300.


User currently offlinePanais From Cyprus, joined May 2008, 446 posts, RR: 0
Reply 2, posted (4 years 9 months 5 days 3 hours ago) and read 18715 times:

It seems that Boeing has gotten the entire airplane design wrong. There is definitely something wrong with the way they make decisions.

They seem fixated at replacing their existing lines, 767 with the 787, 757 with this Light Twin, the 747-400 with the 747-8. To add to that they are considering replacing the 777 with another model. If they do a 737 narrow-body replacement, then there will be 5 families that they need to design, test, certify, built, deliver and support.

Airbus is getting it right.
A380 for VLA
A350 for Wide-body
A320 for Narrow-body.

Anything else is just fillers like the A330 for the missions that it is very good on.

They might have some gaps at the 250 seat narrow-body/widebody medium range or a 450 seat wide-body long range but you cannot be everything to everybody.


User currently offlineRheinwaldner From Switzerland, joined Jan 2008, 2198 posts, RR: 5
Reply 3, posted (4 years 9 months 4 days 22 hours ago) and read 18638 times:



Quoting Panais (Reply 2):
It seems that Boeing has gotten the entire airplane design wrong. There is definitely something wrong with the way they make decisions.

They seem fixated at replacing their existing lines, 767 with the 787, 757 with this Light Twin,

I don't agree. That proposal is extremely bold. It would be the first dedicated shortrange widebody clean sheet design since the A300. It would serve a market that never has been lucrative and today is dead (as claimed by many users of this forum). The 753 was still too much plane to offer the efficiency this Y1.5 (good name Keesje!) could offer.

If this proposal is pursued it would mean that Boeing's strategy for the shorthaul business would be:
- Bet on a larger plane that is able to reduce the efficiency to unseen low levels at the cost of flight frequency (airlines would have to reduce the number of planes and the frequency if the overall capacity on the network should remain about the same).

I have experienced a lot of headwind just by illustrating the intention Boeing has. The idea that frequency should be sacrificed to get better efficiency is quite unpopular. The idea that this method should be used for short range traffic is completely off-limits to some.

For me the closest plane to Y1.5 is the A300. Not a stretch or a derivative but from the first penstroke a short-(not-more-medium-than-the-A320)-range-widebody!

The best thing to illustrate this is Boeing refusal to build in TATL range! We can only imagine how eager they are not to sacrifice efficiency for range:
How much would the efficiency penalty be if a 3000nm plane would be beefed up to offer Transatlantic ranges? One would assume not much, but Boeing refuses even to spend that small amount of performance at the cost of stellar short range efficiency!


User currently offlineRoseFlyer From United States of America, joined Feb 2004, 9378 posts, RR: 52
Reply 4, posted (4 years 9 months 4 days 16 hours ago) and read 18524 times:

The article is a touch outdated, but floating out the idea of a light weight twin aisle is an interesting concept. I don't see it personally working personally. There aren't that many airlines operating larger planes on shorter routes. I can think of a few in Europe, Asia and Australia, but not that many.

Quoting Keesje (Thread starter):


The enormous 737 / A320 backlogs IMO ain't what they look like, both Airbus and Boeing are cutting back production.

737 production has not been cut back. 777 production went down, but 737 is stable and has been since the last rate increase a couple years ago. It's at the highest rate it ever has been at.



If you have never designed an airplane part before, let the real designers do the work!
User currently offlineMSNDC9 From , joined Dec 1969, posts, RR:
Reply 5, posted (4 years 9 months 4 days 13 hours ago) and read 18487 times:

757 replacement in a 2+2+2 config would be quite nice. Quick to turn and fall right between a 757 and 767 in fusealage diameter and length. Perfect for short haul routes between hubs and large markets or between to coast to coast large markets.

User currently offlineRoseflyer From United States of America, joined Feb 2004, 9378 posts, RR: 52
Reply 6, posted (4 years 9 months 4 days 10 hours ago) and read 18436 times:



Quoting MSNDC9 (Reply 5):
757 replacement in a 2+2+2 config would be quite nice. Quick to turn and fall right between a 757 and 767 in fusealage diameter and length. Perfect for short haul routes between hubs and large markets or between to coast to coast large markets.

I would prefer it being 3 x 3 with a 3 inch wider seat instead of the extra aisle. I don't know if airlines agree.



If you have never designed an airplane part before, let the real designers do the work!
User currently offlineThegeek From Australia, joined Nov 2007, 2638 posts, RR: 0
Reply 7, posted (4 years 9 months 4 days 9 hours ago) and read 18424 times:



Quoting RoseFlyer (Reply 4):
The article is a touch outdated, but floating out the idea of a light weight twin aisle is an interesting concept. I don't see it personally working personally. There aren't that many airlines operating larger planes on shorter routes. I can think of a few in Europe, Asia and Australia, but not that many.

Couldn't part of the reason for that be that there is no plane optimized for such a role?

I do agree, though, that stopping just short of a TATL range is probably a mistake.


User currently offlineKeesje From , joined Dec 1969, posts, RR:
Reply 8, posted (4 years 9 months 4 days 3 hours ago) and read 18385 times:



Quoting MSNDC9 (Reply 5):
757 replacement in a 2+2+2 config would be quite nice. Quick to turn and fall right between a 757 and 767 in fusealage diameter and length. Perfect for short haul routes between hubs and large markets or between to coast to coast large markets.

Years ago I played with the idea. A little wider then A320 to enable 2-2-2 (which a percentage cinema like folding seats) and 2-1-2 premium for short trips and various other configurations for medium trips.



User currently offlineThegeek From Australia, joined Nov 2007, 2638 posts, RR: 0
Reply 9, posted (4 years 9 months 3 days 4 hours ago) and read 18255 times:



Quoting Keesje (Reply 8):
Years ago I played with the idea. A little wider then A320 to enable 2-2-2 (which a percentage cinema like folding seats) and 2-1-2 premium for short trips and various other configurations for medium trips.

Why are you obsessed with 2-2-2 in economy? The only way it could ever happen is if it could be shown that it's worth paying a weight & fuel penalty for faster turn times. I would doubt this. Also, there's nothing green about it.

I'd think that the best "Light Twin" would be around 3500-4000nm range, 2-4-2 in economy and LD3 containers in the hold. I.e. an A300, but with updated technology. Perhaps I am wrong.


User currently offlineTSS From United States of America, joined Dec 2006, 3050 posts, RR: 5
Reply 10, posted (4 years 9 months 3 days 4 hours ago) and read 18245 times:



Quoting Thegeek (Reply 9):
Why are you obsessed with 2-2-2 in economy? The only way it could ever happen is if it could be shown that it's worth paying a weight & fuel penalty for faster turn times. I would doubt this. Also, there's nothing green about it.

But that's only an extra half metre or so of width over 737/757 and A32x, which isn't such a big deal.

Quoting Thegeek (Reply 9):
I'd think that the best "Light Twin" would be around 3500-4000nm range, 2-4-2 in economy and LD3 containers in the hold. I.e. an A300, but with updated technology. Perhaps I am wrong.

That would be about a metre and a half wider than 737/757 and A32x which in my book is a wide-body and hardly a "light twin". Also, in a single-class layout that would be only 37 rows for 296 seats which would give the aircraft's fuselage a profile similar to a blimp: Great for rotation on takeoff, but probably not all that aerodynamically efficient at cruise.



Able to kill active threads stone dead with a single post!
User currently offlineRheinwaldner From Switzerland, joined Jan 2008, 2198 posts, RR: 5
Reply 11, posted (4 years 9 months 2 days 21 hours ago) and read 18197 times:



Quoting TSS (Reply 10):
wide-body and hardly a "light twin".

That must not be a contradiction. The structural efficiency of a widebody 300 seater should be better than that of a similarily sized narrowbody.

What is the best plane ever in the seat/MEW metrics? I assume the A300 is the best or one of the best.

For a 250-300 seater I would prefer a widebody. The range should have no influence on that design decision.

Quoting Thegeek (Reply 9):
I'd think that the best "Light Twin" would be around 3500-4000nm range, 2-4-2 in economy and LD3 containers in the hold. I.e. an A300, but with updated technology. Perhaps I am wrong.

I see the value of such a plane. Back to the roots! The first in this category (A300) set the standart!

I would expect stellar CASM of such a plane on short-to-medium routes. Maybe even the best CASM of any plane flying on this planet!


User currently offlineRoseFlyer From United States of America, joined Feb 2004, 9378 posts, RR: 52
Reply 12, posted (4 years 9 months 2 days 20 hours ago) and read 18173 times:



Quoting TSS (Reply 10):

But that's only an extra half metre or so of width over 737/757 and A32x, which isn't such a big deal.

You don't think that is a big deal? That's probably 5% weight increase on the airplane with an off the cuff guess. Larger fuselage means beefier structure, not just more skin. 5% increase in weight means more than 5% increase in fuel burn. Why on earth would an airline want a 5% increase in fuel burn with absolutely zero increase in revenue potential? Is cutting 5 minutes off turn times going to recover that cost? Is it going to be so much drastically more comfortable that economy passengers (ie most cost sensitive) will go to it?

I think 2x2x2 is a dumb idea in economy. I doubt we'll ever see another twin aisle with less than 8 abreast.



If you have never designed an airplane part before, let the real designers do the work!
User currently offlineMSNDC9 From , joined Dec 1969, posts, RR:
Reply 13, posted (4 years 9 months 2 days 18 hours ago) and read 18145 times:



Quoting Thegeek (Reply 9):
I'd think that the best "Light Twin" would be around 3500-4000nm range, 2-4-2 in economy and LD3 containers in the hold. I.e. an A300, but with updated technology. Perhaps I am wrong.

You just described the 787-3 which has sold like hot cakes...


User currently offlineRacko From Germany, joined Nov 2001, 4856 posts, RR: 20
Reply 14, posted (4 years 9 months 2 days 16 hours ago) and read 18126 times:

The 787-3 was too big to be a real A300 replacement. Remember, it would have been a variant of a ~8000nm aircraft, the A300 was purpose-built.

User currently offlineRoseFlyer From United States of America, joined Feb 2004, 9378 posts, RR: 52
Reply 15, posted (4 years 9 months 2 days 16 hours ago) and read 18116 times:



Quoting MSNDC9 (Reply 13):

Quoting Thegeek (Reply 9):
I'd think that the best "Light Twin" would be around 3500-4000nm range, 2-4-2 in economy and LD3 containers in the hold. I.e. an A300, but with updated technology. Perhaps I am wrong.

You just described the 787-3 which has sold like hot cakes...

I still don't understand two aisles if you are below 8 abreast.

The problem with the wider fuselage is not the drag. Yes it punches a bigger hole through the air, but for less time. The big problem is that with engines on the wings, the size of the tail will keep increasing as the fuselage gets shorter. An 8 abreast 120 passenger plane is possible, but the rudder and elevators would have to be humongous and very heavy. The 737NG has a pretty hurkin big rudder in order to deal with the short moment arm due to the short fuselage and the high powered engine out scenario.

I don't want to seem too argumentative as I have quite a bit of respect for Keesje challenging the norms with aircraft design. However, I am an aircraft designer for a living and constantly have to evaluate many conditions when working on designs and take into account every factor. With aircraft design, it is almost assumed that the way it has always been done is better than new ways. You have to prove that a new concept is better. While airplanes might seem high tech, you'd be impressed if you looked at a plane to see the number of carryover parts from old designs. There are thousands of parts flying around newly built 737s and 747s that were drawn by hand in the 1960s by engineers. The technology for many things just hasn't changed that much. What has happened though is that those venerable designs have been refined and perfected over the years so that they can surpass the capabilities of newer technologies.



If you have never designed an airplane part before, let the real designers do the work!
User currently offlineThegeek From Australia, joined Nov 2007, 2638 posts, RR: 0
Reply 16, posted (4 years 9 months 2 days 12 hours ago) and read 18076 times:



Quoting MSNDC9 (Reply 13):
You just described the 787-3 which has sold like hot cakes...

Yes, but that's not exactly optimised for the purpose. Isn't it too heavy? Also, it's 8.5 abreast in economy, which mightn't be quite right.

And didn't that only come into being because the Japanese wanted a plane that could fit existing gates? History has taken a dim view of such planes.

37 rows & 296 seats isn't that much shorter than a 767-300, which in QF config has 40 rows. It's not that short really.


User currently offlineKeesje From , joined Dec 1969, posts, RR:
Reply 17, posted (4 years 9 months 1 day 2 hours ago) and read 17921 times:

thnx for your comments. Reasons to make a "light twin" a little wider then a 3-3 could be
* structural efficiency (I think a little wider fuselage could be lighter when it becomes this long)
* twin aisles isn't an extra, its solving a problem. NWA colleagues told me 757 disembarkation is pushing limits. A person at row 13 taking extra time is holding up 100 fellow passengers
* Long haul / premium cabin flexibility. For longer flights narrow 3 3 flights proved their restrictions. Wider cabin enables roomy 3 3, premium 2 1 2, pods, 1 2 1, etc.
* Cargo/luggage capasity is restricted. A wider cabin would facilitate A320 type cargo containers and pallets and bigger luggage bins.

There is more to it then just 2 2 2 in economy..


User currently offlinePPVRA From Brazil, joined Nov 2004, 8876 posts, RR: 40
Reply 18, posted (4 years 9 months 21 hours ago) and read 17886 times:

Aside from capacity differences with the 783, sounds like it would be designed as a high-cycle widebody. Not the same kind of beast as the 783. I don't know if Boeing made changes to the 783 to increase cycles, if that's even feasible, but surely it wouldn't be optimized for short/medium-haul.

I like the idea overall, and if there isn't much of a market today, I think there will be. Congestion and lack of space for airport expansion will keep pushing the average size of aircraft up, at least at major airports.

[Edited 2009-07-25 07:01:22]


"If goods do not cross borders, soldiers will" - Frederic Bastiat
User currently offlineTdscanuck From Canada, joined Jan 2006, 12709 posts, RR: 80
Reply 19, posted (4 years 9 months 19 hours ago) and read 17856 times:



Quoting Keesje (Reply 17):
* structural efficiency (I think a little wider fuselage could be lighter when it becomes this long)

I'm not sure that works. At these size scales, you're probably sizing fuselage skin thickness by damage requirements, not strength, so you wouldn't gain anything on the skin. Frames would geat heavier. That leaves your stringers shrinking to make up for all the weight gain of the bigger skin. But the skin goes up with the square of the diameter increase, so I'm pretty sure you'll gain more skin than you'll save in stringers.

Quoting Keesje (Reply 17):
* Cargo/luggage capasity is restricted. A wider cabin would facilitate A320 type cargo containers and pallets and bigger luggage bins.

Definitely true, but you could also double-bubble for the same effect.

Tom.


User currently offlineKeesje From , joined Dec 1969, posts, RR:
Reply 20, posted (4 years 8 months 4 weeks 1 day ago) and read 17708 times:



Quoting Tdscanuck (Reply 19):
At these size scales, you're probably sizing fuselage skin thickness by damage requirements, not strength, so you wouldn't gain anything on the skin

I think critical skin thickness would more be a restriction building a light 8 abreast airframe. Building a long tube you need the skin and structure to carry the load / moments induced by its lenght. Skin would likely be thicker then thinner then required to width stand external point loads. Long airframes like the A340-600 and B757-300 fusealges are relatively heavy because of it. More cross section would probably make them lighter.

A powerpoint of Greenliner, a more conventional configuration I made two yrs ago on a bigger, wider narrow body.
http://i191.photobucket.com/albums/z160/keesje_pics/greenliner-1.jpg?t=1248687630

I think on North Atlantic routes (Western Europe - Eastern USA) 230-250 seats two class such an aircraft could beat any existing / planned aircraft. OEW, drag, fuel consumption, pollution, operating costs all considerably lower then twin aisles like the A330-200, 787-8 and 767-300ER. But still with acceptable cabin / comfort levels, contrary to the 757's. Read trip reports on those Atlantic 757 flights..


User currently offlineMSNDC9 From , joined Dec 1969, posts, RR:
Reply 21, posted (4 years 8 months 3 weeks 6 days 14 hours ago) and read 17548 times:



Quoting RoseFlyer (Reply 15):
I still don't understand two aisles if you are below 8 abreast.

Like the 767?

Its clear the next generation narrowbody, even if 3+3 is going to be wider. Bombardier has already established the standard of seat width with Embraer steeping in first with the E-Jets, Boeing with the 787 and Airbus with the A350. So you have one of several new dimensions at play here:

In 3+3 Configurations:

Embraer Type Seat (18.25"): Minimum cabin width 143-144" (18" Aisle)
Bombardier (18.5/19"): Minimum Cabin width 148" (20" Aisle)
Boeing 787 Standard (18.5" Seat): Minimum cabin width 148-149" (21.5" Aisle)
Airbus 350 Standard (19.5" Seat): Minimum cabin width 153" (20" Aisle)

So lets call it 148" interior width

A 2+2+2 with the 18.25" seat (a good balance): 164"/18" Aisle
A 2+2+2 with 18" Seat: 162"/18" Aisle

Being 2+2+2 you can probably still get by with the 17.25" seat because people will feel less cramped then they do with the dreaded middle. That would be a 158" width.

Its not like several feet are being added here, and obviosuly the exterior width will be much larger, but it's going to be closer to the 757/A320/737 than it would be to a 767 and a lot faster to turn around up above 150 seats.


User currently offlineZvezda From Lithuania, joined Aug 2004, 10511 posts, RR: 64
Reply 22, posted (4 years 7 months 3 weeks 3 days 21 hours ago) and read 16685 times:



Quoting Keesje (Reply 17):
twin aisles isn't an extra, its solving a problem. NWA colleagues told me 757 disembarkation is pushing limits. A person at row 13 taking extra time is holding up 100 fellow passengers

2-2-2 is not the optimal solution to faster disembarkation. Airbus and Boeing have both done tests and found that 3-3 with a 30inch aisle disembarks faster than 2-2-2 with two 20inch aisles. The reason seems to be that at about 30 inches, the aisle doesn't get blocked because there is enough space to get around passengers fumbling with their possessions. 20inch aisles are subject to blockage regardless of how many of them there are.


User currently offlineTSS From United States of America, joined Dec 2006, 3050 posts, RR: 5
Reply 23, posted (4 years 7 months 3 weeks 3 days 20 hours ago) and read 16665 times:



Quoting Zvezda (Reply 22):
Airbus and Boeing have both done tests and found that 3-3 with a 30inch aisle disembarks faster than 2-2-2 with two 20inch aisles. The reason seems to be that at about 30 inches, the aisle doesn't get blocked because there is enough space to get around passengers fumbling with their possessions. 20inch aisles are subject to blockage regardless of how many of them there are.

Which only makes sense. Also, there is usually more than one passenger fumbling with their possessions, so two 20 inch aisles could easily be blocked as well. Furthermore, a single 30 inch aisle would allow pax to get around the carts and make their way to the lavs during meal/drink service.



Able to kill active threads stone dead with a single post!
User currently offlineXT6Wagon From United States of America, joined Feb 2007, 3321 posts, RR: 4
Reply 24, posted (4 years 7 months 3 weeks 3 days 17 hours ago) and read 16615 times:

2-2-2 with 17.2" seats and minimum width asiles would require minimal extra width over a A320. The flexiblity from having that bit of extra width would be huge for airlines. The requirements for using containers for belly cargo are already a limiting factor on width, which is why it costs little to go that extra little bit and get flexiblity for selecting the seating they desire for thier own missions.

25 Keesje : In my example I made a percentage of the middle seats fodable to make moving between aisles during (de)boarding possible. With 2-2-2 airlines could s
26 Flighty : This sounds totally pointless. A 767-200 or 767-300 SR are not what any airline really needs right now. They are insane, IMHO. It is probably misinfor
27 Thegeek : I've never understood the 7 abreast in the 767, and after learning more about planes I understand it less. You add all the weight for an extra aisle,
28 Flighty : Absolutely, the 763ER is still a great plane today. New ones are still being built. IMO, at six abreast you can feed a great many people into airport
29 Rheinwaldner : Therefore the focus lays on CASM. Did you know that the A300 once reduced CASM by 66% over other short range planes of its time? Surely large shortra
30 Panais : The best option will be to take the A330-300, remove frames to the length of the A300 and then design a new composite wing and new landing gear that
31 Post contains images Keesje : A300-600 : Operating empty 120,150kg (264,875lb) A330-200 : Operating empty 90,115kg (198,665lb) The A330 (& 787) are for long range & very expensive
32 Thegeek : According to wikipedia, it's 90,900kg. About the same as the A332. Where this concept could come undone is finding suitable engines. Would a cropped
33 Rheinwaldner : This is an important point. More and more we must think in thrust classes. Beside the 777 there exists no aircraft which set efficiency standards and
34 Panais : More like.... A300-600 : Operating empty 90,115kg (198,665lb) A330-200 : Operating empty 120,150kg (264,875lb)
35 Keesje : I switched. Key message is shortening / stripping an efficient long haul machine doesn't make it an efficient short machine. Ask Boeing (787-3).
36 GST : Last semester at uni we had a design project for a new mid-widebody airliner designed to take long haul routes, but with one or more intermediate sto
37 MSNDC9 : They don't want a 767-200/300 they have a 767-300 in the 787-8 and they want a 757-200/300 replacement with a bit more range and similar field perfor
38 Post contains images Keesje : I once thought Bombardier / operators might at some point fit 6 abreast Thompson seats in the C-series for short haul. Improving seatcount, pitch & e
39 Metroliner : First off, Keesje, I must say, you do have a great sense of invention when it comes to aircraft. I hope you're either working in the industry or quali
40 Starlionblue : You can't have more than 3 abreast without an aisle on both sides due to evacuation requirements.
41 Metroliner : I must admit I didn't know that, Starlionblue, but surely the duty of progress is to facilitate change?
42 DocLightning : Not when that change puts people in danger. A evac will always be a evac, no matter how advanced aircraft get, and so people need to get out.
43 Metroliner : I acknowledge that. But there's no reason to believe that we will never have an evacuation procedure that doesn't allow us to safely evacuate a row o
44 Starlionblue : Sure. But you'd have to prove that you can evacuate in 90 seconds and just as "easily" as today. Someday the paradigm might change, but currently the
45 Metroliner : Ah, like in the old slam-door trains we used to have in the UK (only finished in 2007 I believe, and some still running!).
46 GST : Good god the extra weight that would add would be terrifying. There is a LOT of extra structure around any door on a pressurized aircraft, much much
47 Thegeek : I wonder what the regulators would think of the once proposed (on a.net) 50% wider aisle in a narrowbody? Might go some way to helping the evac probl
48 Starlionblue : It might indeed. However (and I speculate here) I don't think the aisle is the bottleneck in this case. It's the length and narrowness of the passage
49 Post contains links keesje : The "Light Twin" surface again. "Yet, one of the reasons why Pratt & Whitney has "gone as high as 40,000lb of thrust is" that there are "airlines
50 planemaker : That sort of conflicts with wider single aisle is faster than twin aisle.
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